مرکز منطقه ای اطلاع رساني علوم و فناوري - Influence of Fortification with Inulin and Hi-maize on Acidity and Viability of Starter Culture in Probiotic Yoghurt

Abstract :

in this study, the effect of fortification with inulin and resistant starch (Hi-maize) on yoghurt starter and probiotic bacteria survival, as well as acidity properties of set-type probiotic yoghurt containing Lactobacillus acidophilus were investigated. Milk was fortified with inulin or Hi-maize at 2% and 4% ratios whereas control group had no supplement. Samples fortified with Hi-maize had higher lactic acid value than those fortified with same ratio of inulin. Lactic acid percentages increased significantly in all probiotic yoghurts at the end of storage in comparison to the first day (p 0.05). The highest viable counts of Streptococcus thermophilus were enumerated in the sample fortified with 2% Hi-maize during 14 days of storage. The control sample had as high viable counts of Lactobacillus bulgaricus as the sample fortified with 4% Hi-maize, except first day of the storage. The highest viability of L. acidophilus was detected in control and the sample fortified with 4% Hi-maize on 7^th and 14^th day whereas the highest value was reported for the control sample at the end of the storage. L.acidophilus populations ranged from 6.30 to 7.95 log cfu/g in probiotic yoghurts during 21 days of refrigerated storage. Therefore, all experimental yoghurts presented probiotic viability above the minimum recommended level of 6 log cfu/g suggested for beneficial health effects.